(fə-rā'mən) Pluralforamina (fə-rām'ə-nə) or foramensAn opening or short passage, especially in the body. ◇ The large opening in the base of the skull through which the spinal cord passes is called the foramen magnum (māg'nəm). ◇ The opening in the septum between the right and left atria of the heart, present in the fetus but usually closed soon after birth, is the foramen ovale (ō-vāl'ē, -vā'lē, -vä'-).